- 放下；放低：
He let down a bucket into the well to draw water.
他把吊桶放进井里打水。
- (使)松动；放松；放慢；松劲；松懈：
Don't let down even if you're nearing the destination.
即使快到目的地也不要松劲。
- 放长(衣服等)：
She wanted to have her skirt let down several centimetres.
她想把裙子放长几厘米。
- 使失望；辜负…的期望：
He let his wife down when he failed to obtain promotion.
他没有得到提升，令他妻子失望。
- 损坏…的威信；使…丢脸：
The manager thought they had let down the firm.
经理认为他们给公司丢了脸。
- (在需要帮助或紧要关头时)背叛；出卖；抛弃：
He let me down when I was in deep trouble.
当我深陷困境时，他背叛了我。
- (在着陆前)使飞机下滑；(飞机着陆前)减速下降：
The plane let down gently before landing at the airport.
飞机在机场着陆以前徐徐下降。
- 放掉…的气：
They played a joke on him by letting down the tyres of his bike.
他们捉弄他，把他的自行车的轮胎放了气。
- 降低(标准等)